Conventionally, there have been combustion gas seals for injectors of the type shown, for example, in FIGS. 13 and 14.
FIG. 13 is a schematic structural diagram showing a state, in which an injector is mounted to an engine head. FIG. 14 is a schematic diagram for describing a seal structure of a combustion gas seal for injectors according to conventional art.
Here, in the case where an injector 50 is mounted to an engine head 60, it is necessary to prevent leakage of combustion gas from a neighborhood of the mounted portion of the injector 50.
Thus, washer-shaped seals 100 and 200 are conventionally provided in two locations on the mount of the injector.50 as shown in FIG. 13 to prevent leakage of combustion gas.
These seals 100 and 200 are formed from a metal such as copper. As shown in FIG. 14, these seals 100 and 200 carry out sealing by a clamping force Q due to a clamping force obtained when the injector 50 is mounted to the engine head 60.
Here, as shown, for example, in FIG. 13, the clamping force is obtained by a clamp 70 pushing the injector 50 due to the clamp 70 being clamped to the engine head 60 by a screw 71.
However, in the case of the configuration of the above-described conventional art, the number of parts increases because, in order to carry out the sealing, parts such as sleeves made of ductile metals (copper, brass, etc.) are necessary in addition to the metal washer-shaped seals 100 and 200.
Also, as mentioned above, because the metal washer-shaped seals 100 and 200 are made to seal using a clamping force, the clamp 70, the sleeve, and the seals 100 and 200 contact each other as like metal members. Therefore, vibration is promoted by vibration resulting from the engine and the like, which leads to noise because large sounds are generated by the portions of metal contact.
Moreover, load based on vibrations and heat causes reduction in the clamping force whereby sealing performance is degraded with time.
It is an object of the present invention to provide a combustion gas seal for injectors and a seal structure disposed therewith, in which the number of parts is reduced, vibration and noise are reduced, and sealing performance is improved.